It is known how to prepare the ethyl ester of methyltartronic acid by oxidizing, with HNO.sub.3 at 98% or with KMnO.sub.4, in an alkaline environment, the ethyl methylmalonate.
According to other methods, the above said esters are generally prepared by hydrolysis of methyl-bromo-malonic acid with barite water and by subsequent esterification with an alcohol, or by acid alcoholysis of alpha-cyanolactic acid (cyanohydrin of pyruvic acid) or of 2-acetoxy-2-methylmalonitrile (1-acetoxy-1,1-dicyanoethane).
None of these methods, however, proves satisfactory for a utilization on a commercial scale.
In fact, said methods involve the use of expensive and not easily available raw materials, such as methylmalonic acid or the ethyl ester thereof and the pyruvic acid, or provide very unsatisfactory yields, or require the use of toxic and hazardous-to-handle substances, such as hydrocyanic acid.